The overall purpose of this project is to correlate membrane structure with function in Gram positive bacteria using Staphylococcus aureus as the model test system. Of particular interest is to define the function (or functions) of mesosomes. The topics of present interest are: chemical and immunochemical localization of lipoteichoic acid in S. aureus; characterization of the structure of staphylococcal lipoteichoic acid; and analysis of the steps involved in lipoteichoic acid biosynthesis and its possible function as related to the mesosome.